A cryogenic silicon micro-strip and pure-CsI detector for detection of antihydrogen annihilations

A new kind of detector for the end products of antihydrogen annihilations, operating at liquid nitrogen temperatures, was designed, developed and built for the ATHENA experiment at CERN. Requirements to be met were low-temperature operation (80 K) in a high magnetic field (4 T), compact size, low-power consumption (5 W) and high granularity. The detector consists of two layers of each 16 double-sided silicon micro-strip modules (16 cm long), surrounded by 192 pure-CsI scintillation crystals ( approximately equals 4 cm**3), read by avalanche photo diodes. The frontend electronic also working at 80 K is realised in VLSI CMOS technology and features a self- triggering capability.